Combined cooling unit and drip pan



June 231-193 R.; W. KRITZERETYAL 2,045,529 I COMBINED COOL ING U NIT AND DRIP PAN Fild A ri115, 1955 air circulating means, for the same, are comparadisclosed in the Richard Patented .Fune 23, 1936 plus) res cago, 1111.,

2,645,529 cormmsn 000mm nm'r AND pair PAN Richard W. Kritz er and Anthony F.

assignors to Peerless lice Hoesel, Chi- Machine Cooling and combination drippan and tively old in the art, as

W; Kritzer applications No. 711,485 filed February 16, 1934, and No. 712348 filed February 23, 1934, and No. 715,800 filed March 16, 1934, which are claimed to be improvements upon the prior disclosed art and to which our present joint application relates.

One of the disadvantages of all the combinations used in'the art, prior to our joint invention, is the fact that these prior devices would not function correctly whenever compartment temperatures close to 32 F. had to be maintained.

The majority of refrigerating plants, using cooling units and combination drip pan and air circulator means, are automatic in operation. The maximum capacity of the refrigerant ciroulating compressor and its associated cooling units is in excess of the heat to be absorbed by'the cooling units; therefore, the cycle of operation is alternately in the on and off-time cycle.

The major heat load of the refrigerating plants, referred to above, is-due to that of the heat in leakage through the floor, ceiling and walls' of the compartments. v age, per unit area of the boundary surfaces, is entirely dependent upon the type of insulation, the thickness of the insulation andthe-temperature difference between the outside andinside of the refrigerated compartment.

, and maximum storage All of the above mentioned plants are operated in such cycles, as to maintain the compartment temperatures between certain definite limits. For instance, in the storage of meats, the individual compartments may be desired to have temperatures maintained between 32 F and 34 E,

which gives an average temperature of 33 F. If the compartments were maintained between 29 F. and 37 F.', there would also, then, be an average temperature of 33 F.; however, while in the former case the maximum variation in temperature is 2 F., in the latter case the variation in temperature would be 8 F. A minimum temperature variation, as is well known, is the best for minimum dehydration of the stored product time, during which the palatabiiity and fresh appearance of the stored product may be retained. Therefore, there has been a" constant, endeavor, in the refrigerating art, to decrease compartment temperature-variationsto the minimum, which would not seriously impair the thermal efficiency ,of the refrigerating system, increase-the cost of operation or add to the complexity of the installation.

cooling unit to its The rate of this heat leak between adjacent surfaces completely'fille'd with frost.

space, orat least necessitates a largergross space than that necessary for storage only in the compartment, it becomes necessary to condense the lowest possible physical di-. Plain refrigerant piping occupies a considerable volume of space per unit surface areaytherefore, these plants are equipped with finned refrigerant conduit cooling units, which occupya muchlower volume of space per unit area than the equivalent area of plain piping. These cooling units are termed fin coils.

Whenever the surface area of a cooling unit is mensions.

" condensed, in its boundary dimensions, such as in a fin coil, there is comparatively small space between adjacent surfaces, and since, during the on-cycle time, these cooling units are maintained at a temperature appreciably lower than 32 F., frost forms upon these surfaces.

If this frosting is cumulative, during each onbe long before the spaces, and for the purpose therethrough, will be cycle time, it will not of allowing air circulation During cumulative frosting, the spaces thereby, the original the cooling unit is substantially decreased, which by decreasing the heat absorptioncapacity of the cooling unit, cuts down-the efficiency of the re-'-.'

frigerating system, increases the cost of operation and possibly, in some instances, no longer allows the maintenance of the desired tempera? tures. 1 f

Because of the above, it may be readily realized that. a complete defrosting of the cooling unit surfaces, during each off-time cycle, is the most desirable pondition for the maximum efficiency. i i In order to ole tions'affectlng the rlyportray the actual condidefrosting of cooling units,

per hour. Assume a cooling unit in the compartment and, with its associated compressor, having a heat absorption. capacity of 8,000 B.t.'u. per

will then be '15 percent entirely defrost the moisture deposited upon its.

and the filling of surface area of we shall take a typicalexample. Assume a com-, partment having a heat load rate of 6,000 B.t.u.

' 2, which pass through tion capacity edges surfaces during the on-time cycle, then in order to get a thorough defrosting, at the 75 percent total operating time necessary to maintain the desired compartment temperatures, theon-time cycle will have to be not less than 30 minutes. If, under the above conditions, a temperature variation of 4 F. Obtains in the compartment and a temperature variation not to exceed 2 F; must be attained, then it is imperative that some means be employed to cut the defrosing time in half, allowing an on-time cycle time of 15 minutes and an off-time cycle of 5 minutes.

All of the foregoing relates to the drip pan as well as the cooling unit since, during the defrosting of the cooling unit, all of the deposited moisture does not drop from the cooling unit in the formof water. During the operation of the cooling unit, small icicles form at the lowermost edges of the cooling unit, and whenever they attain a certain cycle, drop into Dan is not at a the drip pan, where, if the drip sufi'iciently elevated temperature to thoroughly melt them before the start of the on-time cycle, there will be a gradual build up of ice in the drip pan channels and eventually the channels will overflow and defeat their purpose.

One of the objects of our joint invention is to cut down the time of a finned coil cooling unit.

Another object is to increase the volume of the convection circulation of air through a cooling unit.

Another object is to increase the heat absorp of a finned refrigerant conduit cooling unit. I A further object is to quickly raise the ternperature of a drip pan during the off-time cycle of a refrigerating system. v

Referring to the drawing:

Figure 1 is an end elevational view of a cooling unit and combination drip pan and air circulator for the same.v j I 4 Figure 2 is a side elevational view of Figure 1.

Figure 3 is an end elevational view of a modified cooling unit for comparatively low temperature use. I Y

Figure 4 is a fragmentary plan view of Figures 1 and 2 unit to a single inlet.

- serted into the refrigerant conduit to provide a spiral passage adjacent the internal walls of the conduit. In Figures 1, and 2, the parallel reaches of the refrigerant conduit I are joined by return bends the suspension end plates 3, thereby making a continuous refrigerant circuit in each of the right and left-hand sections, shown in Figure 1, which are manifolded at their inlets 4 and their outlets 5. Upon the parallel conduit reaches I, are mounted a multiplicity of spaced apart rectangular fins I5, which increase the effective heat absorption surface of the conduits I. The above comprises the cooling unit. Directly below the cooling unit, and suspended from the suspension end plates 3, is a combina-- tion drip pan and air circulator comprised of a plurality of louvre channels 6, of which the lower for receiving the moisture dripping from the cooling unit during the off-time cycle. All of the channels spill into a common collector 8, having an outlet 9 whichtcan be connected to a sewer.

size, they, during the off-time volume and necessaryfor the defros'ing substantially separated.

air'intake to the cooling surfaces.

1, being bent upwardly,-provide a trough ployed.

' the suspension means for; the drip pan assembly.

In Figure 3, all of the elements of Figures 1 and 2 obtain and, therefore, has been added to the number of the similar elements of Figures 1 and 2.

Figure 5 shows a spiral ribbon I2 having a helical pitch I3 and an outside diameter I4, which is slightly greater than the internal diameter of the conduit I, into which it is inserted. The purposes and advantages its equivalents, is clearly explained in the Richard W. Kritzer and Anthony F. Hoesel joint application, Serial No. 758,065, filed December '18, 1934, for Conduit for the circulation of refrigerants.

During the operation of the'device, the circula- This cooling of the airreduces its consequently increases unit volume, which tends for the cooled air to drop through the cooling unit, allowing warmer and lighter air to pass into the cooling unit. This convection circulation of the air is continuous as long as the cooling unit temperature is below 1 that of the air temperature.

If the cooling unit surfaces, during the operation, did not drip moisture, there would be no need for any auxiliary device below the cooling unit. However, because of moisture drip, it becomes necessary to provide some means of catching the of this ribbon, or

its weight per same and allowing it to pass to a drain or otherwise. 1

The circulation of the air, during the, operation of the cooling unit, has a comparatively low velocity and, therefore, any obstructions placed in the line of natural air circulation tend to restrict the air flow and decrease the heat absorption capacity of the cooling unit.

In the drawing I and 3, it will be noticed that the fins I5, of adjacent parallel reaches} I are This separation performs two functions; first, the separation-provides a path for comparatively warm air, the

circulation of which is induced by the descending cold air streamjadjacent the surfaces; second,

the separation provides a greater area for warm instance, the induced circulation of warm air bathe: the louvre channels 6 and keeps them at an increased temperature above that of the' temperature of the cold air stream passing between adjacent louvre channels. This allows any .small ice particles, which may drip from the cooling unit during the off-time cycle, to thoroughly melt and pass inliquid form through the drain connection 9, before time cycle. This particular feature allowsuus to operate with much narrower. compartment temperature differentials than the structures disclosed in the previously mentioned applications, which vtend to cumulatively become fllled an'dthe drip then overflows onto the floor of the compartment or the goods stored therein, which condition can only be overcome In the first,

the start of the on-' refreeze these ice 1 particles until the 'troughs shown at I and I 01 by increasing the compartment temperature g ferentials between the on-time cycle andiofftime cycle, unless the presentffivention isv emduits of the cooling I2, inserted within the conunits, increases the internal, refrigerant wetted, surface or the conduits and thereby increases the heat absorption of the coolin! unit. In actual tests of cooling units without this spiral ribbon, we have found out that the heat absorption capacity per degree Fahrenheit dropped rather sharply at comparatively high temperature differentials between the temperature of the air and the temperature of the circulating refrigerant. We definitely determined that this loss in efficiency occurred due-to conditions within the conduit, rather than conditions outside the conduit, and the results of our experiments are embodied in the spiral ribbon and its equivalents as disclosed in our previously mentioned joint application.

While the above describes the preferred embodiment of our joint invention, we do not wish to limit it thereto, but rather to the specific combinations set forth within the following claims.

We claim:

' 1. The combination f a refrigerant conduit cooling unit having spaced apart parallel reaches with a multiplicity of spaced apart fins mounted The spiral ribbon thereon and individual to each reach, the spacing 1 of the parallel reaches being substantially greater than the fin dimensions parallel to'the line of spacing and a multiple louvred drip pan below the assembly, and eachbottom parallel reach of the'co0ling unit being served by a single louvre.

the cooling unit 2. The combination of a refrigerant conduit parallel reaches mounted thereon and individual to each reach, the spacing cooling unit having spaced apart with a multiplicity of spaced apart fins of the parallel reaches being substantially greater than the fin dimensions parallel to the line of spacing and a multiple louvred drip pan below the assembly, and each bottom paralle reach of being served by a si le louvre, having a projected horizontal width greater than the width of the fin. 3-,The combination of a finned refrigerant conduit cooling unit having plural sections manifolded to a single inlet and mounted upon coma multiple louvred drip pan each bottomreach being served by a single louvre;

' 4. The combination of a refrigerant conduit mon spacing means,

cooling unit having spaced apart parallel reaches with a multiplicity of spaced apart fins mounted thereon and individual to each reach, the spacing of the parallel reaches being substantially greater thanthe fin dimensions parallel tothe line of spacing and a multiple louvred drip pan below the assembly, and each bottomvparallel reach of the cooling unit being served by a single louvre, the said conduit having a spiral passage t c-adjacent its internal walls.

folded to a single inlet line of spacing with a multiplicity cooling unit having spacedapart parallel reaches with a multiplicity of spaced apart fins mounted thereon and individual to each reach, the spacing of the parallel reaches being substantially greater than the fin'dimensions parallel to the line of spacing and a multiple louvred drip pan below the assembly. and each bottom parallel reach of the cooling unitbeing served by a single louvre, having a projected horizontal width greater than the width of having a spiral passage adjacent its internal walls.

6. The combination of a finned refrigerant conduit cooling unit having plural sections maniand mounted upon common spacing'means; a multiple louvred drip pan below the assembly, and each bottom reach being served by a single louvre, the said conduit having a spiral passage adjacent its internal walls.

7. The combination of a refrigerant conduit cooling unit having spaced apart parallel reaches with a multiplicity of spaced apart fins mounted thereon and individual to each reach, the spacing of the parallel reaches being substantially greater than the-fin dimensions parallel to the line of spacing and providing a the fins of adjacent conduit reaches and a multi- -ple louvred drip pan below the assembly, the upper edge of the louvre being positioned within the vertical prolongation of said space.

8. The combination of a refrigerant conduit cooling unit having spaced apart parallel reaches with a multiplicity of spaced apart fins mounted thereon and individual to each reach, the spacing of the parallel reaches being substantially greater than the fin dimensions parallelto the and providing a space between the fins of adjacent conduit reaches and a multiple louvred drip pan below the assembly, and each 5. The combination of a refrigerant conduit the fin, the said conduit 1 space between i bottom parallel reach of the cooling unit being v served by a single louvre being positioned longation of said space.

9. The combination of a refrigerant conduit cooling unit having spaced apart parallel reaches. of spaced apartfins mounted thereon and individual to each reach, the spacing of the parallel reaches being substantially greater than the fin dimensions parallel to the line of louvre,'the upper edge of the within the vertical prospacing and providing a space between thefins-of adjacent conduit reaches and a multiple louvred drip pan below the assembly, and each bottom parallel reach ofthe cooling unit being served by a single louvre, having a projected horizontal width greater than the width of the fin, the upper edge or the louvre being positioned within the vertical prolongation of said space.

RICHARD w.

ANTHONY l. HOESEL. 

